llext: move current test to a hello_world subdir

In preparation for multiple tests, move the current hello_world test
to its own subdirectory. Also, merge the llext compilation in the
parent CMakeLists.txt.

Signed-off-by: Luca Burelli <l.burelli@arduino.cc>

tests/subsys/llext/CMakeLists.txt

@@ -1,26 +0,0 @@
-# Copyright (c) 2023 Intel Corporation.
-# SPDX-License-Identifier: Apache-2.0
-
-cmake_minimum_required(VERSION 3.20.0)
-find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
-project(llext_test)
-
-add_subdirectory(hello_world)
-
-target_sources(app PRIVATE src/test_llext_simple.c)
-
-target_include_directories(app PRIVATE
-  ${ZEPHYR_BASE}/include
-  ${ZEPHYR_BASE}/kernel/include
-  ${ZEPHYR_BASE}/arch/${ARCH}/include
-  )
-
-set(gen_dir ${ZEPHYR_BINARY_DIR}/include/generated/)
-
-generate_inc_file_for_target(
-  app
-  ${HELLO_WORLD_LLEXT}
-  ${gen_dir}/hello_world.inc
-  )
-
-add_dependencies(app hello_world)

tests/subsys/llext/hello_world/CMakeLists.txt

@@ -3,20 +3,26 @@
 
 cmake_minimum_required(VERSION 3.20.0)
 find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
-project(hello_world)
+project(llext_hello_world_test)
 
-if(NOT CONFIG_LLEXT_TEST_HELLO)
-  # test disabled, nothing to do
-else()
+target_sources(app PRIVATE
+  src/test/test_llext_simple.c
+)
 
-  set(llext_src_file ${PROJECT_SOURCE_DIR}/hello_world.c)
-  set(llext_bin_file ${PROJECT_BINARY_DIR}/hello_world.llext)
+target_include_directories(app PRIVATE
+  ${ZEPHYR_BASE}/include
+  ${ZEPHYR_BASE}/kernel/include
+  ${ZEPHYR_BASE}/arch/${ARCH}/include
+)
 
-  add_llext_target(hello_world
-    OUTPUT  ${llext_bin_file}
-    SOURCES ${llext_src_file}
-  )
+# Compile a simple hello world llext to an include file
+set(llext_src_file ${PROJECT_SOURCE_DIR}/src/llext/hello_world.c)
+set(llext_bin_file ${ZEPHYR_BINARY_DIR}/hello_world.llext)
+set(llext_inc_file ${ZEPHYR_BINARY_DIR}/include/generated/hello_world.inc)
 
-  set(HELLO_WORLD_LLEXT ${llext_bin_file} PARENT_SCOPE)
+add_llext_target(hello_world
+  OUTPUT  ${llext_bin_file}
+  SOURCES ${llext_src_file}
+)
 
-endif()
+generate_inc_file_for_target(app ${llext_bin_file} ${llext_inc_file})